Process of refining oils



June 16, 1931.

A. R. MOORMAN ET AL PROCESS OF REFINING OILS Filed Jan. 4, 1929 PatentedJune 16, 1931 uNrraDv STATES PATEnT OFFICE A ARTHUR R. MOORMAN, OF WOODRIVER, ILLINOIS, IRVING C. CARPENTER, AOIE NEW ROCHELLE, NEW YORK,ASSIGNORS TO CONTACT FILTRATION COMPANY, OF SAN FRANCISCO, CALIFORNIA, ACORPORATION OF DELAWARE .PROCESS OF REFINING OILS ApplicationV f ledJanuary 4, 1929. Serial No. 330,309.

This invention relates to the treatment of oils and particularly relatesto a process of neutralizing and decolorizing oils with nely dividedsolid adsorbents.

process is applicable to the rening of vegetable and animal oils, it isparticularly directed to the treatment of petroleum oils such aslubricating oils.

By the use of the term adsorbent as hereinafter applied, we refer to theuse of any finely divided or comminuted solid material capable ofexerting an adsorbing action upon the oil being treated and includingsuch materials as natural decolorizing or adsorbing clays, acid treatedor otherwise activated clays, various forms of carbon, silica and othermaterial.

Most oilssuch as lubricating oil stocks,'are

acid treated during refining, and it has been discovered previously thatsuch oils containing small quantities of acid and acid reaction productsmay be neutralized without the application of alkaline solutions byContact with comminuted solid adsorbents such as the mineralmontmorillonite and other decolorizing clays.

When it is desired to neutralize acid oil with a finely dividedadsorbent, it is general practice to agitate the acid oil with aquantity of adsorbent sufficient to produce the desiredB neutralization.In view of the fact that most of these adsorbents exert decolorizingeffects upon oil, it is customary to heat mixtures of oil andadsorbentso as to simul- 35 taneously neutralize and decolorize the oil,the heat being applied so as to produce temperature conditions whichfacilitate the decolorizing and neutralizing reactions.V This process,while attractive from an operating standpoint, entails the usey of largeamounts of adsorbents per unit volume of oil treated and, for thisreason, the following modification has been suggested as being aneconomic improvement over the hereinabove described single steptreatment. Y

This second method of treating acid oils so as to produce a neutralizedand decolorized .oil consists in agitating the acid oil with adecolorizin 21j-so as to gat er all suspended sludge and tar Althoughthe` clay at a moderate temperature resulting from a previous treatmentwith acid and then removing the clay together with the` sludge and tarby filtration. The cleaned oil, freed of tar and suspended sludge, isthen agitated with fresh clay at a moderate temperature, or at aslightly higher temperature, so as to complete the neutralization', andagain filtered to remove the clay. v The neutralized oil is thencontacted with a further quantity' agitated together at a moderatetemperature,l

say 10U-450 F., so as to effect neutralization, such decolorization astakes placel at this stage being merely incidental. The proportion ofdecolorization which takes place in this step depends somewhat upon thecharacter of the oil. After the neutralized oil is separated from thisspent clay or other adsorbent,.it is then agitated with a relativelysmall quantity of fresh adsorbent, the mixture being heated to asuitable decolorizing temperature. The adsorbent is then removed fromthe treated oil in any suitable manner and such removed and partly spentadsorbent may then be utilized for neutralizing a further quantity ofacid oil.

The neutralization and major decolorization are therefore accomplishedsuccessively, and a different batch of clay is used to complete thedecolorizing than that used for neutralizing, it having been found thatclay having expended its decolorizing power 1s still effective as aneutralizing agent. Partially spent clay or other adsorbent which hasbeen spent only in decolorizing oil is used t0 neutralize the acid oil,any decolorizing power remaining in the partially spent adsorbent actingto partially decolorize the stock during the neutralizing step.After/ruf separation of the completely spent adsorbent from theneutralized stock, fresh clay or other adsorbent is added thereto andthe decolorizin operation completed.

T is cycle may be repeated indefinitely,l

- colorized with a fresh batch of adsorbent and such adsorbent, havingbeen partially spent in adsorbing the coloring matter from the oil, maybe used for neutralizing a further quantity of oil. The finishedneutralized and decolorized oil obtained by this method is generally ofbetter color than that obtained y former methods, while the total amountof adsorbent used per unit volume of finished oil will be found to befrom ten to thirty percent less. This great reduction in quantity ofadsorbent required to neutralize and decolorize oils is apparently dueto the-fact that a relatively small quantity of adsorbent will exert amore complete decolorizing elfect upon an oil if such oil is firstneutralized by means of partly spent adsorbent from such decolorizingreaction.

An object of this invention is to provide a method of neutralizing anddecolorizing oils in which the quantity of adsorbent required ismaterially reduced from that generally required. f

Another object is to utilize an adsorbentofor neutralizing acid oils,which adsorbent has previously expanded all or part of its decolorizingpower on neutralized oil.

Another object is to provide a method of neutralizing and decolorizingacid oils in separate steps.

A still further object is to provide a method of using partially spentadsorbents for neutralizin acid oils.

Anotiier object is-to provide a method o neutralizing 'and decolorizingacid oil in separatesteps, the decolorizing step being the source ofadsorbent for the neutralizing ste ther objects and advantages of ourprocess will be apparent from the following description of a process ofneutralizing and decolorizing petroleum oils, the application of thisprocess to the treatment of petroleum oils being stated in detail merelyfor purposes of illustration. i

Reference will also be had to the appended drawing, in which the varioussteps and apparatus required are diagrammatically illustrated. It is tobe understood, however, that the hereinafter described detail processmay be materially modified without departing from the invention, and theinvention is not limited to a process employing all of the steps or theprecise apparatus shown in the attached drawing, the invention includingall such modifications as come within the sco e of the appended claims.y

enerally, 1n carrying out our rocess, it is necessary to first obtainabatch o partially spent clay or other adsorbent. For example, it may beobtained by using a batch of clay to decolorize oil which has previouslybeen neutralized by caustic or other agent. The cycle can be mostconveniently started by neutralizing an acid oil with a small batch ofclay, discardino' such clay and then completely decolorizmg theneutralized oil with a fresh batch of clay. In the decolorizingoperation the clay loses a part of its eiectiveness but is stillsufficiently active to neutralize acid stock. The artially spent clay isthen preferably added) direct to a batch of acid oil which isneutralized and also partially decolorized if the clay retains any ofits decolorizing properties, the clay being thoroughly mixedA with theoil and the mixture heated to a temperature of ap roximately 250 F. orhigher and preferab y with the use of steam.

The mixture may then be cooled below the temperature of substantialoxidation if the temperature employed in the neutralizing step is suchthat substantial oxidation of the oil would take place on exposure tothe atmosphere, after which the spent clay may be removed from themixture by filtration or other means of separating solids from li uidsand discarded, leaving the neutralize oil in condition for furthertreatment.

The neutralized oil may be next charged into a treater equipped withmeans for heating and agitating the contents, and fresh clay added in anamount suitable to accomplish the desired decolorization, as previousldetermined. The clay is well mixed wit the oil and the mixture broughtto the proper temperature for decolorization and maintained at suchtemperature until the decolorizing reaction is completed. While themixture is being brought up to this temperature, any low boilingconstituents which may be present in the 011 may be removed bydistillation, whereupon the operation may be preferably accompanied bysteaming.V

The clay used in this step, although-its major decolorizing propertiesare exhausted, still retains its neutralizing power, and afterseparation from the oil by filtering is retained for use intheneutralization of a fresh batch of acid oil. The hot oil-clay mixturemay be sent direct to the ilter and the oil cooled after separation orthe mixture may be iven a complete or partial cooling before. tra.-tion. In any event care should'be taken to avoid contact with theatmosphere until the temperature of the oil is reduced below that ofrapid oxidation. In separating the decolorizing clay from the mixture itis not essential that the partially spent clay be substantially denudedof oil, as any oil entraned in the filter cake is carried overinto thefresh batch ofacid oil which is to be neutralized by means of thepartially spent clay.

While the removal of low boiling constituents from the neutralized oilhas been described as taking place after-the fresh clay has been`addedto the neutralized oil, it may be desirable to remove such fractionsprior to the addition of fresh clay. This is for the reason that, undersome circumstances, the decolorizing operation may be more efficientlycarried out on substantially reduced stock. In such cases theneutralized oil may be heated to distill off the low boilingconstituents, after which the heated oil may be mixed with the freshclay and brought to the proper decolorizing temperature. As before, theclay is only partially spent in the decolorizing step, and after beingfiltered from the oil is used as a neutralizing agent for a fresh batchof acid oil.

Any suitable forms of apparatus may be used in carrying out the processof theginvention, which may be performed as a complete cycle or asseparate steps as desired, an example of cycle operation being shown inthe accompanying drawing.

Referring to the drawing, which represents a flowdiagram, the acid oilmay enter the system through a line 1 and be mixed with a partiallyspent adsorbent such as clay which has been partially spent in thedecolorization of neutralized oil. Such partially spent'adsorbent may bemixed with the acid oil entering the systeml through line 1 in asuitable mixing device such as the mixing tank 2, the partially spentadsorbent being supplied from a source to be hereinafter dcscribed andindicated by line 3. The mixture of acid oil and partially spentadsorbent from the vessel 2 may then be pumped by the pump 4 and throughline 5 into another mixing tank 6. Means may be provided for heating themixture in tank 6, such means being illustrated on the drawing by theheater 7, a portion of the mixture of oil and spent-adsorbent beingcirculated from tank 6 by means of the pump 8 through line 9 into heater7 and returned to tank 6 through the line 10. Suitable valves such asthe valves 11, 12 and 13 may be employed to regulate the flow orcirculation of the mixture through the heater 7.

The acid oil is neutralized by the partially separating means such asthe filter 17, the oil being discharged from the filter by line 18,while the discharge of spent clay is indicated by line 19.

The neutralized oil discharged from the filter 17 by line 18 may then bepumped by pump means 20 and through line 21 into a suitable mixing meanssuch as the tank 22, wherein the neutralized oil is intimately contactedwith fresh adsorbent, preferably in finely divided form, suppliedthrough a suitable feeding means such as the hopper 23. If desired, themixing means 22 may take the form of a tank or treating vessel in whichthe mixture of oil and clay or other adsorbent may be heated so as todistill off the moisture and low boiling constituents which may be'present, for which a vapor outlet 24 may be provided. The neutralizedoil, together with fresh adsorbent added thereto, is preferably raisedto a sufficiently high temperature to enable the decolorization to takeplace with greatest efficiency. Such heating may be attainedbycirculating the mixture of oil and fresh'adsorbent from the treatingvessel 22 through a line provided with a valve 25 and by means of a pump26 through a heater 27 which mayf'contain tubes 28.

Aline 29 provided with a valve 30 may lead from the heater 27 back tothe treating .vessel 22, thereby permitting the pump 26 to circulate acertain quantity of the mixture of oil and adsorbent through the heateruntil the desired temperature isreached. The oil and adsorbent may thenbe pumped by the means 26 through the lines 28 and 29 into line 3l byclosing the valve 30 in line 29 and opening valve 32 in line 31.

The system may also be operated continuously to tank 22 and the materialcontinuously removed through line 31 by regulation of valve 32 or by anadditional pump in line 31.

In this manner the heated mixture of oil and adsorbent may be sent to acooler 33 and therefrom into a suitable separating means such as thefilter 34 wherein the decolorized oil may be separated from thepartially spent adsorbent. The oil may be discharged through line 35and, if desired, sent through a secondary cooler 36 before it is sent toa suitable storage, or for further treatment through line 37. Thepartially spent adsorbent separated from the finished oil in theseparating means or filter 34 may then be spent adsorbent in tanks 2 and6 and, after mixed with acid oil by sending to the mixing suchneutralization, the mixture of oil and spent adsorbent may then bepassed through line 14 into a cooler 15 where the temperature of the oilmay be reduced to below the temperature of rapid oxidation, if suchtemperatures were reached by passing the oil through the heater 7.Generally, it is not i necessary to cool. From the cooler 15 the mixtureof oil and spent adsorbent may be pumped by a pump means 16 into asuitable tank 2 through a line or other suitable means 3.

By utilizing the process above described, a

superior decolorizing effect may be obtained with a much smallerquantity of adsorbent or decolorizing clay than is necessary undermethods used heretofore. In some instances the amount of decolorizingclay required has been as low as seventy-five percent of that formerlyused. The re-use of the clay in the manner described has resulted ineliiciencies of ten to thirty percent over present methods andmaterially reduces the cost of neutralizing and decolorizing acidtreated oils.

We claim:

1. The process of refining acid treated oils Which comprises heating theacid oil with a comminuted solid adsorbent previously used fordecolorizing neutralized oil, separating the adsorbent from the oil,adding fresh adsorbent to the oil, heating the mixture to above 212 F.to decolorize theoil, and nally separating the decolorized oil from theadsorbent.

2. The process of refining lubricating oils containing acid reactionproducts, comprising agitating partially spent adsorbent with an acidoil in the presence of heat to neutralize the oil7 separating the spentadsorbent from the oil, adding fresh adsorbent to the neutralized oil,heating the mixture to above 212 F. to effect a decolorizing reaction onthe oil, separating the partially spent adsorbent fromthe decolorizedoil, and then contacting said partially spent adsorbent with a freshbatch of acid oil to neutralize the same.

3. The process of refining acid treated lubricating oils comprisingmixing an acid oil with adsorbent partially spent in decolorizingneutralized oil, heating the mixture to about 250 F. to neutralize saidacid oil, cooling the mixture below the temperature of rapid oxidationof the oil, separating the neutralized oil from the spent adsorbent,mixing the neutralized oil with fresh adsorbent, heating the mixture toa temperature aboveabout 250 F. to decolorize the oil, cooling themixture below the temperaturel of rapid oxidation of the oil, separatingthe decolorized oil from the partially spent adsorbent, and thencontacting the partially spent adsorbent with a fresh batch of acidtreated oil to neutralize the sanie.

Signed at Wood River, Ill., this 5th day of December 1928.

ARTHUR R. -MOORMAN. Signed at New York N. Y. this 8th day of A November1928. f

IRVING C. CARPENTER.

